Light-emitting device, light-emitting device package, and light unit

ABSTRACT

A light-emitting device, according to one embodiment, comprises: a light-emitting structure comprising a first conductive semiconductor layer, an active layer which is underneath the first conductive semiconductor layer, and a second conductive semiconductor layer which is underneath the active layer; a reflective electrode which is arranged under the light-emitting structure; a first metal layer which is arranged under the reflective electrode and is electrically connected to the second conductive semiconductor layer; a second metal layer which is arranged under the reflective electrode and is insulated from the first metal layer; and a contact portion for electrically connecting the second metal layer and the first conductive semiconductor layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims under 35 U.S.C. §119 to Korean PatentApplication No. 10-2012-0061372 filed on Jun. 8, 2012, which is herebyincorporated by reference.

TECHNICAL FIELD

The embodiment relates to a light-emitting device, a light-emittingdevice package, and a light unit.

BACKGROUND ART

A light-emitting diode (LED) has been extensively used as one oflight-emitting devices. The LED converts electrical signals into theform of light such as infra-red light, ultra-violet light, and visiblelight by using the characteristic of a compound semiconductor.

As the light efficiency of the light-emitting device is increased, theLED has been used in various fields such as display apparatuses andlighting appliances.

DISCLOSURE Technical Problem

The embodiment provides a light-emitting device, a light-emitting devicepackage, and a light unit, capable of lowering operating voltage andimproving light extraction efficiency.

Technical Solution

A light-emitting device according to the embodiment includes alight-emitting structure including a first conductive semiconductorlayer, an active layer under the first conductive semiconductor layer,and a second conductive semiconductor layer under the active layer; areflective electrode under the light-emitting structure; a first metallayer disposed under the reflective electrode and electrically connectedto the second conductive semiconductor layer; a second metal layerdisposed under the reflective electrode and insulated from the firstmetal layer; and a contact part electrically connecting the second metallayer to the first conductive semiconductor layer.

A light-emitting device package according to the embodiment includes abody; a light-emitting device on the body; and first and second leadelectrodes electrically connected to the light-emitting device, whereinthe light-emitting device includes a light-emitting structure includinga first conductive semiconductor layer, an active layer under the firstconductive semiconductor layer, and a second conductive semiconductorlayer under the active layer; a reflective electrode under thelight-emitting structure; a first metal layer disposed under thereflective electrode and electrically connected to the second conductivesemiconductor layer; a second metal layer disposed under the reflectiveelectrode and insulated from the first metal layer; and a contact partelectrically connecting the second metal layer to the first conductivesemiconductor layer.

A light unit according to the embodiment includes a substrate; alight-emitting device on the substrate; and an optical member serving asan optical path for light emitted from the light-emitting device,wherein the light-emitting device includes a light-emitting structureincluding a first conductive semiconductor layer, an active layer underthe first conductive semiconductor layer, and a second conductivesemiconductor layer under the active layer; a reflective electrode underthe light-emitting structure; a first metal layer disposed under thereflective electrode and electrically connected to the second conductivesemiconductor layer; a second metal layer disposed under the reflectiveelectrode and insulated from the first metal layer; and a contact partelectrically connecting the second metal layer to the first conductivesemiconductor layer.

Advantageous Effects

The light-emitting device, the light-emitting device package, and thelight unit according to the embodiment can lower operating voltage andimprove the light extraction efficiency.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing a light-emitting device according to theembodiment.

FIG. 2 is a view showing a first metal layer and a contact part of alight-emitting device according to the embodiment.

FIGS. 3 to 7 are views showing a method of fabricating a light-emittingdevice according to the embodiment.

FIG. 8 is a view showing a light-emitting device package according tothe embodiment.

FIG. 9 is a view showing a display device according to the embodiment.

FIG. 10 is a view showing another example of the display deviceaccording to the embodiment.

FIGS. 11 to 13 are views showing a lighting apparatus according to theembodiment.

FIGS. 14 and 15 are views showing another example of a lightingapparatus according to the embodiment.

BEST MODE Mode for Invention

In the description of the embodiments, it will be understood that, whena layer (or film), a region, a pattern, or a structure is referred to asbeing “on” or “under” another substrate, another layer (or film),another region, another pad, or another pattern, it can be “directly” or“indirectly” over the other substrate, layer (or film), region, pad, orpattern, or one or more intervening layers may also be present. Such aposition of the layer has been described with reference to the drawings.

The thickness and size of each layer shown in the drawings may beexaggerated, omitted or schematically drawn for the purpose ofconvenience or clarity. In addition, the size of elements does notutterly reflect an actual size.

Hereinafter, a light-emitting device, a light-emitting device package, alight unit, and a method for fabricating the light-emitting deviceaccording to the embodiments will be described in detail with referenceto accompanying drawings.

FIG. 1 is a view showing a light-emitting device according to theembodiment.

As shown in FIG. 1, the light-emitting device according to theembodiment may include a light-emitting structure 10, a reflectiveelectrode 17, a first metal layer 50, a second metal layer 55 and acontact part 75.

The light-emitting structure 10 may include a first conductivesemiconductor layer 11, an active layer 12, and a second conductivesemiconductor layer 13. The active layer 12 may be interposed betweenthe first conductive semiconductor layer 11 and the second conductivesemiconductor layer 13. The active layer 12 may be provided under thefirst conductive semiconductor layer 11, and the second conductivesemiconductor layer 13 may be provided under the active layer 12.

For instance, the first conductive semiconductor layer 11 may include anN-type semiconductor layer doped with N-type dopants serving as firstconductive dopants, and the second conductive semiconductor layer 13 mayinclude a P-type semiconductor layer doped with P-type dopants servingas second conductive dopants. In addition, the first conductivesemiconductor layer 11 may include a P-type semiconductor layer, and thesecond conductive semiconductor layer 13 may include an N-typesemiconductor layer.

For example, the first conductive semiconductor layer 11 may include anN-type semiconductor layer. The first conductive semiconductor layer 11may be realized by using a compound semiconductor. The first conductivesemiconductor layer 11 may be realized by using a group II-VI compoundsemiconductor, or a group III-V compound semiconductor.

For example, the first conductive first semiconductor layer 11 may berealized by using a semiconductor material having a compositionalformula of In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1). For example,the first conductive first semiconductor layer 11 may include oneselected from the group consisting of GaN, AlN, AlGaN, InGaN, InN,InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP doped with N-typedopants such as Si, Ge, Sn, Se, and Te.

The active layer 12 emits light having a wavelength corresponding to theenergy band gap difference according to materials constituting theactive layer 13 through the combination of electrons (or holes) injectedthrough the first conductive semiconductor layer 11 and holes (orelectrons) injected through the second conductive semiconductor layer13. The active layer 12 may have one of a single quantum well (SQW)structure, a multi-quantum well (MQW) structure, a quantum dotstructure, and a quantum wire structure, but the embodiment is notlimited thereto.

The active layer 12 may be realized by using a compound semiconductor.The active layer 12 may be realized by using a semiconductor materialhaving a compositional formula of InxAlyGa1-x-yN (0≦x≦1, 0≦y≦1,0≦x+y≦1). When the active layer 12 has an MQW structure, the activelayer 12 may be formed by stacking a plurality of well layers and aplurality of barrier layers. For example, the active layer 12 may have acycle of InGaN well layer/GaN barrier layer.

For example, the second conductive semiconductor layer 13 may include aP-type semiconductor layer. The second conductive semiconductor layer 13may be realized by using a compound semiconductor. For example, thesecond conductive semiconductor layer 13 may be realized by using agroup II-VI compound semiconductor, or a group II-V compoundsemiconductor.

For example, the second conductive semiconductor layer 13 may berealized by using a semiconductor material having a compositionalformula of InxAlyGa1-x-yN (0≦x≦1, 0≦y≦1, 0≦x+y≦1). For example, thesecond conductive semiconductor layer 13 may include one selected fromthe group consisting of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN,AlGaAs, GaP, GaAs, GaAsP, and AlGaInP doped with P-type dopants such asMg, Zn, Ca, Sr, and Ba.

Meanwhile, the first conductive semiconductor layer 11 may include aP-type semiconductor layer and the second conductive semiconductor layer13 may include the N-type semiconductor layer. In addition, asemiconductor layer including an N-type or P-type semiconductor layermay be additionally provided under the second conductive semiconductorlayer 13. Accordingly, the first light-emitting structure 10 may have atleast one of an NP junction structure, a PN junction structure, an NPNjunction structure, or a PNP junction structure. In addition, impuritiesmay be doped into the first conductive semiconductor layer 11 and thesecond conductive semiconductor layer 13 with uniform or non-uniformdoping concentration. In other words, the first light-emitting structure10 may have various structures, and the embodiment is not limitedthereto.

In addition, a first conductive InGaN/GaN superlattice structure orInGaN/InGaN superlattice structure may be formed between the firstconductive semiconductor layer 11 and the active layer 12. In addition,a second conductive AlGaN layer may be formed between the secondconductive semiconductor layer 13 and the active layer 13.

The reflective electrode 17 may be disposed under the light-emittingstructure 10. An ohmic contact layer 15 may be further disposed betweenthe light-emitting structure 10 and the reflective electrode 17. Thefirst metal layer 50 may be disposed under the light-emitting structure10 and around the ohmic contact layer 15. The first metal layer 50 maybe disposed around a lower portion of the light-emitting structure 10.The first metal layer 50 may be disposed around the reflective electrode17.

The first metal layer 50 may be electrically connected to the secondconductive semiconductor layer 13. A first region of the first metallayer 50 may be may make contact with a bottom of the second conductivesemiconductor layer 13 and a second region of the first metal layer 50may extend outward from the first region. The first metal layer 50 maymake contact with a bottom of the reflective electrode 17.

For example, the ohmic contact layer 15 may include a transparentconductive oxide layer. For example, the ohmic contact layer 15 mayinclude at least one selected from the group consisting of an ITO(Indium Tin Oxide), an IZO (Indium Zinc Oxide), an AZO (Aluminum ZincOxide), an AGZO (Aluminum Gallium Zinc Oxide), an IZTO (Indium Zinc TinOxide), an IAZO (Indium Aluminum Zinc Oxide), an IGZO (Indium GalliumZinc Oxide), an IGTO (Indium Gallium Tin Oxide), an ATO (Antimony TinOxide), a GZO (Gallium Zinc Oxide), an IZON (IZO Nitride), ZnO, IrOx,RuOx, NiO, Pt and Ag.

The reflective electrode 17 may include a material having highreflectance. For example, the reflective electrode 17 may include ametal including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt,Cu, Au, and Hf, or an alloy thereof. In addition, the reflectiveelectrode 17 may be formed in a multi-layer of the metal or the alloythereof and a transmissive conductive material such as an ITO(Indium-Tin-Oxide), an IZO (Indium-Zinc-Oxide), an IZTO(Indium-Zinc-Tin-Oxide), an IAZO (Indium-Aluminum-Zinc-Oxide), an IGZO(Indium-Gallium-Zinc-Oxide), an IGTO (Indium-Gallium-Tin-Oxide), an AZO(Aluminum-Zinc-Oxide), or an ATO (Antimony-Tin-Oxide). For example,according to the embodiment, the reflective electrode 17 may include atleast one of Ag, Al, an Ag—Pd—Cu alloy, and an Ag—Cu alloy.

The ohmic contact layer 15 may come into ohmic-contact with thelight-emitting structure 10. The reflective electrode 17 may reflectlight incident thereto from the light-emitting structure 10 to increasethe quantity of light extracted to an outside.

The first metal layer 50 may include at least one of Cu, Ni, Ti, Ti—W,Cr, W, Pt, V, Fe, and Mo. The first metal layer 50 may serve as adiffusion barrier layer.

The light-emitting device according to the embodiment may include thesecond metal layer 55 disposed under the reflective electrode andelectrically insulated from the first metal layer 50. The second metallayer 55 may include at least one of Cu, Ni, Ti, Ti—W, Cr, W, Pt, V, Fe,and Mo. The second metal layer 55 may serve as a diffusion barrierlayer.

The second metal layer 55 may be disposed under the first metal layer50. The light-emitting device according to the embodiment may include afirst insulating layer 53 disposed between the first metal layer 50 andthe second metal layer 55. The first insulating layer 53 may be disposedaround the first metal layer 50. The first insulating layer 53 mayinclude at least one of oxide and nitride. For instance, the firstinsulating layer 53 may include at least one of Al₂O₃, SiO₂, Si₃N₄,TiO₂, and AlN.

In addition, the light-emitting device according to the embodiment mayinclude the contact part 75 which electrically insulates the secondmetal layer 55 from the first conductive semiconductor layer 11. Thecontact part 75 may be formed through the first insulating layer 53. Aplurality of contact parts 75 may be provided. The contact part 75 mayinclude at least one selected from the group consisting of Cr, V, Pt, W,Ti, Zn, Ni, Cu, Al, Ag, and Au.

A first region of the contact part 75 may make contact with a topsurface of the first conductive semiconductor layer 11. A second regionof the contact part 75 may be disposed at lateral sides of the activelayer 12 and the second conductive semiconductor layer 13. A secondinsulating layer 63 may be disposed between the second region of thecontact part 75 and the active layer 12 and between the second region ofthe contact part 75 and the second conductive semiconductor layer 13.

The second insulating layer 63 may electrically insulate the contactpart 75 from the active layer 12. The second insulating layer 63 mayelectrically insulate the contact part 75 from the second conductivesemiconductor layer 13. One end of the second insulating layer 63 may bedisposed on the first conductive semiconductor layer 11. The other endof the second insulating layer 63 may be disposed on the firstinsulating layer 53. A portion of the second insulating layer 63 may bedisposed between the contact part and the first insulating layer 53. Thefirst insulating layer 53 may include at least one of oxide and nitride.For instance, the first insulating layer 53 may include at least one ofAl₂O₃, SiO₂, Si₃N₄, TiO₂, and AlN.

The contact part 75 may be spaced apart from a lateral side of the firstmetal layer 50. For instance, the first metal layer 50, the firstinsulating layer 53 and the contact part 75 may have the structure asshown in FIG. 2. FIG. 2 is a sectional view taken along line A-A of thelight-emitting device shown in FIG. 1.

A plurality of contact parts 75 may be provided. The contact part 75 maybe surrounded by the first insulating layer 53. The contact part 75 maybe electrically insulated from the first metal layer 50 by the firstinsulating layer 53.

A bonding layer 60 and a support member 70 may be disposed under thesecond metal layer 55.

The second metal layer 55 may prevent a material included in the bondinglayer 60 from being diffused to the reflective electrode 17 in theprocess of providing the bonding layer 60. The second metal layer 55 mayprevent a material, such as Sn, included in the bonding layer 60 fromexerting an influence upon the reflective electrode 17.

The bonding layer 60 may include barrier metal or bonding metal. Forexample, the bonding layer 60 may include at least one of Ti, Au, Sn,Ni, Cr, Ga, In, Bi, Cu, Ag, Nb, Pd and Ta. The support member 70 maysupport the light-emitting structure 10 according to the embodimentwhile performing a heat radiation function. The bonding layer 60 may berealized in the form of a seed layer.

The support member 70 may include at least one of semiconductorsubstrates (e.g., Si, Ge, GaN, GaAs, ZnO, SiC, and SiGe substrates)implanted with Ti, Cr, Ni, Al, Pt, Au, W, Cu, Mo, Cu—W, or impurities.For example, the support member 70 may be formed of insulating material.

Meanwhile, the light-emitting device according to the embodiment mayinclude the electrode 80 which is electrically connected to the firstmetal layer 50 and spaced apart from a lateral side of thelight-emitting structure 10. The electrode 80 spaced apart from alateral side of the light-emitting structure 10 may make contact with atop surface of the first metal layer 50.

According to the embodiment, power may be applied to the light-emittingstructure 10 through the reflective electrode 17 and the electrode 80.According to the embodiment, the electrode 80 may be realized in theform of a multiple layer. The electrode 80 may include an ohmic layer,an intermediate layer, and an upper layer. The ohmic layer may include amaterial selected from the group consisting of Cr, V, Pt, W, Ti, and Znto realize ohmic contact. The intermediate layer may be realized byusing a material selected from the group consisting of Ni, Cu, Al andAg. For instance, the upper layer may include Au. The electrode 80 mayinclude at least one selected from the group consisting of Cr, V, Pt, W,Ti, Zn, Ni, Cu, Al, Ag, and Au.

A light extraction pattern may be provided on the top surface of thelight-emitting structure 10. A concavo-convex pattern may be provided onthe top surface of the light-emitting structure 10. For example, thelight extraction pattern provided on the light-emitting structure 10 maybe formed through a PEC (photo electro chemical) etching process.Therefore, according to the embodiment, the light extraction effect tothe outside can be increased.

In the light-emitting device according to the embodiment, a power sourcehaving a first electric potential may be connected to the secondconductive semiconductor layer 13 through the first metal layer 50 andthe reflective electrode 17 and a power source having a second electricpotential may be connected to the first conductive semiconductor layer11 through the second metal layer 55 and the contact part 75. Thus,power may be applied to the light-emitting structure 10 so that theactive layer 12 may emit light. According to the light-emitting deviceof the embodiment, the contact parts 75 may be connected to the firstconductive semiconductor layer 11, so that the current spreading can beimproved. As a result, the operating voltage can be lowered.

Hereinafter, a method of fabricating the light-emitting device accordingto the embodiment will be described with reference to FIGS. 3 to 7.

According to the method of fabricating the light-emitting device of theembodiment, as shown in FIG. 3, the first conductive semiconductor layer11, the active layer 12, and the second conductive semiconductor layer13 may be formed on a substrate 5. The first conductive semiconductorlayer 11, the active layer 12, and the second conductive semiconductorlayer 13 may be defined as the light-emitting structure 10

For example, the substrate 5 may include at least one of a sapphiresubstrate (Al₂O₃), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but theembodiment is not limited thereto. A buffer layer may be interposedbetween the first conductive semiconductor layer 11 and the substrate 5.

For example, the first conductive semiconductor layer 11 may include anN-type semiconductor layer doped with N-type dopants serving as firstconductive dopants, and the second conductive semiconductor layer 13 mayinclude a P-type semiconductor layer doped with P-type dopants servingas second conductive dopants. In addition, the first conductivesemiconductor layer 11 may include a P-type semiconductor layer, and thesecond conductive semiconductor layer 13 may include an N-typesemiconductor layer.

For example, the first conductive semiconductor layer 11 may include anN-type semiconductor. The first conductive semiconductor layer 11 mayinclude a semiconductor material having a compositional formula ofIn_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1. 0≦y≦1, 0≦x+y≦1). For example, the firstconductive semiconductor layer 11 a may include one selected from thegroup consisting of InAlGaN, GaN, AlGaN, AlInN, InGaN, AlN, and InN, andmay be doped with N-type dopants such as Si, Ge, Sn, Se, and Te.

The active layer 12 emits light having a wavelength corresponding to theenergy band gap difference according to materials constituting theactive layer 12 through the combination of electrons (or holes) injectedthrough the first conductive semiconductor layer 11 and holes (orelectrons) injected through the second conductive semiconductor layer13. The active layer 12 may have one of a single quantum well (SQW)structure, a multi-quantum well (MQW) structure, a quantum dotstructure, and a quantum wire structure, but the embodiment is notlimited thereto.

The active layer 12 may be realized by using a semiconductor materialhaving a compositional formula of In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1,0≦x+y≦1). When the active layer 12 has an MQW structure, the activelayer 12 may be formed by stacking a plurality of well layers and aplurality of barrier layers. For example, the active layer 12 may have acycle of InGaN well layer/GaN barrier layer.

For example, the second conductive semiconductor layer 13 may berealized by using a P type semiconductor. The second conductivesemiconductor layer 13 may be realized by using a semiconductor materialhaving a compositional formula of In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1,0≦x+y≦1). For example, the second conductive semiconductor layer 13 mayinclude one selected from the group consisting of InAlGaN, GaN, AlGaN,InGaN, AlInN, AlN, and InN, and may be doped with P-type dopants such asMg, Zn, Ca, Sr, and Ba.

Meanwhile, the first conductive semiconductor layer 11 may include aP-type semiconductor layer and the second conductive semiconductor layer13 may include the N-type semiconductor layer. In addition, asemiconductor layer including an N-type or P-type semiconductor layermay be additionally provided on the second conductive semiconductorlayer 13. Accordingly, the light-emitting structure 10 may have at leastone of an NP junction structure, a PN junction structure, an NPNjunction structure, or a PNP junction structure. In addition, impuritiesmay be doped into the first conductive semiconductor layer 11 and thesecond conductive semiconductor layer 13 with uniform or non-uniformdoping concentration. In other words, the light-emitting structure 10may have various structures, and the embodiment is not limited thereto.

In addition, the first conductive InGaN/GaN superlattice structure orInGaN/InGaN superlattice structure may be formed between the firstconductive semiconductor layer 11 and the active layer 12. In addition,a second conductive AlGaN layer may be formed between the secondconductive semiconductor layer 13 and the active layer 12.

Next, as shown in FIG. 4, the ohmic contact layer 15 and the reflectiveelectrode 17 may be formed on the light-emitting structure 10.

For example, the ohmic contact layer 15 may include a transparentconductive oxide layer. For example, the ohmic contact layer 15 mayinclude at least one selected from the group consisting of an ITO(Indium Tin Oxide), an IZO (Indium Zinc Oxide), an AZO (Aluminum ZincOxide), an AGZO (Aluminum Gallium Zinc Oxide), an IZTO (Indium Zinc TinOxide), an IAZO (Indium Aluminum Zinc Oxide), an IGZO (Indium GalliumZinc Oxide), an IGTO (Indium Gallium Tin Oxide), an ATO (Antimony TinOxide), a GZO (Gallium Zinc Oxide), an IZON (IZO Nitride), ZnO, IrOx,RuOx, NiO, Pt and Ag.

The reflective electrode 17 may include a material having highreflectance. For example, the reflective electrode 17 may include ametal including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt,Cu, Au, and Hf, or an alloy thereof. In addition, the reflectiveelectrode 17 may be formed in a multi-layer of the metal or the alloythereof and a transmissive conductive material such as an ITO(Indium-Tin-Oxide), an IZO (Indium-Zinc-Oxide), an IZTO(Indium-Zinc-Tin-Oxide), an IAZO (Indium-Aluminum-Zinc-Oxide), an IGZO(Indium-Gallium-Zinc-Oxide), an IGTO (Indium-Gallium-Tin-Oxide), an AZO(Aluminum-Zinc-Oxide), or an ATO (Antimony-Tin-Oxide). For example,according to the embodiment, the reflective electrode 17 may include atleast one of Ag, Al, an Ag—Pd—Cu alloy, and an Ag—Cu alloy.

In addition, as shown in FIG. 4, the first metal layer 50 may be formedon the reflective layer 17. The first metal layer 50 may be formedaround the ohmic contact layer 15 and on the reflective layer 17. Thefirst metal layer 50 may include at least one of Cu, Ni, Ti, Ti—W, Cr,W, Pt, V, Fe, and Mo. The first metal layer 50 may serve as a diffusionbarrier layer.

Then, as shown in FIG. 5, the first insulating layer 53 may be formed onthe first metal layer 50. The first insulating layer 53 may be definedwithin the first metal layer 50. The first insulating layer 53 mayinclude at least one of oxide and nitride. For instance, the firstinsulating layer 53 may include at least one of Al₂O₃, SiO₂, Si₃N₄,TiO₂, and AlN.

Meanwhile, above processes for forming layers are illustrative purposeonly and the process sequence may be variously changed.

In addition, as shown in FIG. 6, the second metal layer 55, the bondinglayer 60 and the support member 70 may be provided on the firstinsulating layer 53. The second metal layer 55 may prevent a materialincluded in the bonding layer 60 from being diffused to the reflectiveelectrode 17 in the process of providing the bonding layer 60. Thesecond metal layer 55 may prevent a material, such as Sn, included inthe bonding layer 60 from exerting an influence upon the reflectiveelectrode 17.

The bonding layer 60 may include barrier metal or bonding metal. Forexample, the bonding layer 60 may include at least one of Ti, Au, Sn,Ni, Cr, Ga, In, Bi, Cu, Ag, Nb, Pd and Ta. The support member 70 maysupport the light-emitting structure 10 according to the embodimentwhile performing a heat radiation function. The bonding layer 60 may berealized in the form of a seed layer.

The support member 70 may include at least one of semiconductorsubstrates (e.g., Si, Ge, GaN, GaAs, ZnO, SiC, and SiGe substrates)implanted with Ti, Cr, Ni, Al, Pt, Au, W, Cu, Mo, Cu—W, or impurities.The support member 70 may be formed of an insulating material.

Next, the substrate 5 is removed from the first conductive semiconductorlayer 11. According to one example, the substrate 5 may be removedthrough a laser lift off (LLO) process. The LLO process is a process todelaminate the substrate 5 from the first conductive semiconductor layer11 by irradiating a laser to the bottom surface of the substrate 5.

Then, as shown in FIG. 7, the lateral side of the light-emittingstructure 10 is etched through an isolation etching process to expose aportion of the second metal layer 55 and a portion of the firstinsulating layer 53. The isolation etching process may be performedthrough a dry etching process such as an inductively coupled plasma(ICP) process, but the embodiment is not limited thereto.

A first region of the first metal layer 50 may be disposed under thelight-emitting structure 10. A second region of the first metal layer 50may extend outward from the first region. The second region of the firstmetal layer 50 may horizontally extend from the first region. The secondregion of the first metal layer 50 may be exposed to a lower outerperipheral portion of the light-emitting structure 10.

A light extraction pattern may be provided on the top surface of thelight-emitting structure 10. A concavo-convex pattern may be provided onthe top surface of the light-emitting structure 10. For example, thelight extraction pattern may be formed through a PEC (photo electrochemical) etching process. Therefore, according to the embodiment, thelight extraction effect to the outside can be increased. According tothe embodiment, the top surface of the light-emitting structure 10 mayserve as an N plane, which has a higher roughness than a Ga plane, sothe light extraction efficiency may be further improved.

Next, as shown in FIG. 7, the second insulating layer 63 may be formedon a top surface and a lateral side of the light-emitting structure 10.For instance, the second insulating layer 63 may include at least oneselected from the group consisting of Al₂O₃, SiO₂, Si₃N₄, TiO₂, and AlN.Then, the contact part 75 and the electrode 80 may be formed on thesecond insulating layer 63.

The light-emitting device according to the embodiment may include thesecond metal layer 55 disposed under the reflective electrode andelectrically insulated from the first metal layer 50. The second metallayer 55 may include at least one of Cu, Ni, Ti, Ti—W, Cr, W, Pt, V, Fe,and Mo. The second metal layer 55 may serve as a diffusion barrierlayer.

The second metal layer 55 may be disposed under the first metal layer50. The light-emitting device according to the embodiment may include afirst insulating layer 53 disposed between the first metal layer 50 andthe second metal layer 55. The first insulating layer 53 may be disposedaround the first metal layer 50.

In addition, the light-emitting device according to the embodiment mayinclude the contact part 75 which electrically insulates the secondmetal layer 55 from the first conductive semiconductor layer 11. Thecontact part 75 may be formed through the first insulating layer 53. Aplurality of contact parts 75 may be provided. The contact part 75 mayinclude at least one selected from the group consisting of Cr, V, Pt, W,Ti, Zn, Ni, Cu, Al, Ag, and Au.

A first region of the contact part 75 may make contact with a topsurface of the first conductive semiconductor layer 11. A second regionof the contact part 75 may be disposed at lateral sides of the activelayer 12 and the second conductive semiconductor layer 13. The secondinsulating layer 63 may be disposed between the second region of thecontact part 75 and the active layer 12 and between the second region ofthe contact part 75 and the second conductive semiconductor layer 13.

The second insulating layer 63 may electrically insulate the contactpart 75 from the active layer 12. The second insulating layer 63 mayelectrically insulate the contact part 75 from the second conductivesemiconductor layer 13. One end of the second insulating layer 63 may bedisposed on the first conductive semiconductor layer 11. The other endof the second insulating layer 63 may be disposed on the firstinsulating layer 53. A portion of the second insulating layer 63 may bedisposed between the contact part and the first insulating layer 53. Thefirst insulating layer 53 may include at least one of oxide and nitride.

The contact part 75 may be spaced apart from a lateral side of the firstmetal layer 50. For instance, the first metal layer 50, the firstinsulating layer 53 and the contact part 75 may have the structure asshown in FIG. 2. FIG. 2 is a sectional view taken along line A-A of thelight-emitting device shown in FIG. 1.

A plurality of contact parts 75 may be provided. The contact part 75 maybe surrounded by the first insulating layer 53. The contact part 75 maybe electrically insulated from the first metal layer 50 by the firstinsulating layer 53.

Meanwhile, the light-emitting device according to the embodiment mayinclude the electrode 80 which is electrically connected to the firstmetal layer 50 and spaced apart from the lateral side of thelight-emitting structure 10. The electrode 80 spaced apart from thelateral side of the light-emitting structure 10 may make contact withthe top surface of the first meal layer 50.

According to the embodiment, power may be applied to the light-emittingstructure 10 through the reflective electrode 17 and the electrode 80.According to the embodiment, the electrode 80 may be realized in theform of a multiple layer. The electrode 80 may include an ohmic layer,an intermediate layer, and an upper layer. The ohmic layer may include amaterial selected from the group consisting of Cr, V, Pt, W, Ti, and Znto realize ohmic contact. The intermediate layer may be realized byusing a material selected from the group consisting of Ni, Cu, Al andAg. For instance, the upper layer may include Au. The electrode 80 mayinclude at least one selected from the group consisting of Cr, V, Pt, W,Ti, Zn, Ni, Cu, Al, Ag, and Au.

In the light-emitting device according to the embodiment, a power sourcehaving a first electric potential may be connected to the secondconductive semiconductor layer 13 through the first metal layer 50 andthe reflective electrode 17 and a power source having a second electricpotential may be connected to the first conductive semiconductor layer11 through the second metal layer 55 and the contact part 75. Thus,power may be applied to the light-emitting structure 10 so that theactive layer 12 may emit light. According to the light-emitting deviceof the embodiment, the contact parts 75 may be connected to the firstconductive semiconductor layer 11, so that the current spreading can beimproved. As a result, the operating voltage can be lowered.

FIG. 8 is a view showing a light-emitting device package to which thelight-emitting device according to the embodiment is applied.

Referring to FIG. 8, the light-emitting device package according to theembodiment may include a body 120, first and second lead electrodes 131and 132 formed on the body 120, a light-emitting device 100 provided onthe body 120 and electrically connected to the first and second leadelectrodes 131 and 132 and a molding member 140 that surrounds thelight-emitting device 100.

The body 120 may include silicon, synthetic resin or metallic material,and an inclined surface may be formed in the vicinity of thelight-emitting device 100.

The first and second lead electrodes 131 and 132 are electricallyisolated from each other to supply power to the light-emitting device100. The first and second lead electrode 131 and 132 can improve thelight efficiency by reflecting the light emitted from the light-emittingdevice 100. Further, the first and second lead electrodes 131 and 132may dissipate heat generated from the light-emitting device 100 to theoutside.

The light-emitting device 100 can be installed on the body 120 or thefirst or second lead electrode 131 or 132.

The light-emitting device 100 may be electrically connected to the firstand second lead electrodes 131 and 132 through one of a wire scheme, aflip-chip scheme, and a die-bonding scheme.

The molding member 140 may surround the light-emitting device 100 toprotect the light-emitting device 100. In addition, the molding member140 may include phosphors to change the wavelength of the light emittedfrom the light-emitting device 100.

A plurality of light-emitting device or light-emitting device packagesaccording to the embodiment may be arrayed on a substrate, and anoptical member including a lens, a light guide plate, a prism sheet, ora diffusion sheet may be provided on the optical path of the lightemitted from the light-emitting device package. The light-emittingdevice package, the substrate, and the optical member may serve as alight unit. The light unit is realized in a top view type or a side viewtype and variously provided in display devices of a portable terminaland a laptop computer or a lighting apparatus and an indicatorapparatus. In addition, a lighting apparatus according to anotherembodiment can include a light-emitting device, or a light-emittingdevice package according to the embodiment. For example, the lightingapparatus may include a lamp, a signal lamp, an electric sign board anda headlight of a vehicle.

The light-emitting device according to the embodiment may be applied tothe light unit. The light unit has a structure in which a plurality oflight-emitting devices are arrayed. The light unit may include a displaydevice as shown in FIGS. 9 and 10 and the lighting apparatus as shown inFIGS. 11 to 15.

Referring to FIG. 9, a display device 1000 according to the embodimentincludes a light guide plate 1041, a light-emitting module 1031 forsupplying the light to the light guide plate 1041, a reflective member1022 provided below the light guide plate 1041, an optical sheet 1051provided above the light guide plate 1041, a display panel 1061 providedabove the optical sheet 1051, and a bottom cover 1011 for receiving thelight guide plate 1041, the light-emitting module 1031, and thereflective member 1022. However, the embodiment is not limited to theabove structure.

The bottom cover 1011, the reflective member 1022, the light guide plate1041 and the optical sheet 1051 may constitute a light unit 1050.

The light guide plate 1041 diffuses the light to provide surface light.The light guide plate 1041 may include transparent material. Forexample, the light guide plate 1041 may include one of acryl-basedresin, such as PMMA (polymethyl methacrylate), PET (polyethyleneterephthalate), PC (polycarbonate), COC (cyclic olefin copolymer) andPEN (polyethylene naphthalate) resin.

The light-emitting module 1031 supplies the light to at least one sideof the light guide plate 1041. The light-emitting module 1031 serves asthe light source of the display device.

At least one light-emitting module 1031 is provided to directly orindirectly supply the light from one side of the light guide plate 1041.The light-emitting module 1031 may include a substrate 1033 andlight-emitting devices 100 or the light-emitting device package 200according to the embodiment described above. The light-emitting packages200 may be arrayed on the substrate 1033 while being spaced apart fromeach other at the predetermined interval.

The substrate 1033 may be a printed circuit board (PCB) including acircuit pattern. In addition, the substrate 1033 may also include ametal core PCB (MCPCB) or a flexible PCB (FPCB) as well as the PCB, butthe embodiment is not limited thereto. If the light-emitting devicepackages 200 are installed on the lateral side of the bottom cover 1011or on a heat dissipation plate, the substrate 1033 may be omitted. Theheat dissipation plate may partially make contact with the top surfaceof the bottom cover 1011.

In addition, the light-emitting device packages 200 are installed suchthat light exit surfaces of the light-emitting device packages 200 arespaced apart from the light guide plate 1041 at a predetermineddistance, but the embodiment is not limited thereto. The light-emittingdevice packages 200 may directly or indirectly supply the light to alight incident part, which is one side of the light guide plate 1041,but the embodiment is not limited thereto.

The reflective member 1022 may be disposed below the light guide plate1041. The reflective member 1022 reflects the light, which travelsdownward through the bottom surface of the light guide plate 1041,upward, thereby improving the brightness of the light unit 1050. Forexample, the reflective member 1022 may include PET, PC or PVC resin,but the embodiment is not limited thereto. The reflective member 1022may serve as the top surface of the bottom cover 1011, but theembodiment is not limited thereto.

The bottom cover 1011 may receive the light guide plate 1041, thelight-emitting module 1031, and the reflective member 1022 therein. Tothis end, the bottom cover 1011 has a receiving section 1012 having abox shape with an opened top surface, but the embodiment is not limitedthereto. The bottom cover 1011 can be coupled with the top cover (notshown), but the embodiment is not limited thereto.

The bottom cover 1011 can be manufactured through a press process or anextrusion process by using metallic material or resin material. Inaddition, the bottom cover 1011 may include metal or non-metallicmaterial having superior thermal conductivity, but the embodiment is notlimited thereto.

The display panel 1061, for example, is an LCD panel including first andsecond transparent substrates, which are opposite to each other, and aliquid crystal layer interposed between the first and second substrates.A polarizing plate can be attached to at least one surface of thedisplay panel 1061, but the embodiment is not limited thereto. Thedisplay panel 1061 displays information by using light passing throughthe optical sheet 1051. The display device 1000 can be applied tovarious portable terminals, monitors of notebook computers and laptopcomputers, and televisions.

The optical sheet 1051 is disposed between the display panel 1061 andthe light guide plate 1041 and includes at least one transmissive sheet.For example, the optical sheet 1051 includes at least one of a diffusionsheet, horizontal and vertical prism sheets, and a brightness enhancedsheet. The diffusion sheet diffuses the incident light, the horizontaland/or vertical prism sheet concentrates the incident light onto adisplay region, and the brightness enhanced sheet improves thebrightness by reusing the light to be lost. In addition, a protectivesheet can be provided on the display panel 1061, but the embodiment isnot limited thereto.

The light guide plate 1041 and the optical sheet 1051 can be provided onthe optical path of the light-emitting module 1031 as optical members,but the embodiment is not limited thereto.

FIG. 10 is a view showing another example of a display device accordingto the embodiment.

Referring to FIG. 10, the display device 1100 includes a bottom cover1152, a substrate 1020 on which the light-emitting devices 100 arearrayed, an optical member 1154, and a display panel 1155.

The substrate 1020 and the light-emitting device packages 200 mayconstitute a light-emitting module 1060. The bottom cover 1152, at leastone light-emitting module 1060, and the optical member 154 mayconstitute a light unit.

The bottom cover 1152 can be provided therein with a receiving section1153, but the embodiment is not limited thereto.

In this case, the optical member 1154 may include at least one of alens, a light guide plate, a diffusion sheet, horizontal and verticalprism sheets, and a brightness enhanced sheet. The light guide plate mayinclude PC or PMMA (Poly methyl methacrylate). The light guide plate canbe omitted. The diffusion sheet diffuses the incident light, thehorizontal and vertical prism sheets concentrate the incident light ontoa display region, and the brightness enhanced sheet improves thebrightness by reusing the light to be lost.

The optical member 1154 is disposed above the light-emitting module 1060in order to convert the light emitted from the light-emitting module1060 into the surface light. In addition, the optical member 1154 maydiffuse or collect the light.

FIGS. 11 to 13 are views showing a lighting apparatus according to theembodiment.

FIG. 11 is a top perspective view of the lighting apparatus, FIG. 12 isa bottom perspective view of the lighting apparatus shown in FIG. 11,and FIG. 13 is an exploded perspective view of the lighting apparatusshown in FIG. 11.

Referring to FIGS. 11 to 13, the lighting apparatus according to theembodiment may include a cover 2100, a light source module 2200, aradiator 2400, a power supply part 2600, an inner case 2700, and asocket 2800. The lighting apparatus according to the embodiment mayfurther include at least one of a member 2300 and a holder 2500. Thelight source module 2200 may include the light-emitting device packageaccording to the embodiment.

For example, the cover 2100 may have a blub shape or a hemisphericshape. The cover 2100 may have a hollow structure which is partiallyopen. The cover 2100 may be optically coupled with the light sourcemodule 2200. For example, the cover 2100 may diffuse, scatter, or excitelight provided from the light source module 2200. The cover 2100 may bean optical member. The cover 2100 may be coupled with the radiator 2400.The cover 2100 may include a coupling part which is coupled with theradiator 2400.

The cover 2100 may include an inner surface coated with a milk-whitepigment. The milk-white pigment may include a diffusion material todiffuse light. The roughness of the inner surface of the cover 2100 maybe greater than the roughness of the outer surface of the cover 2100.The surface roughness is provided for the purpose of sufficientlyscattering and diffusing the light from the light source module 2200.

The cover 2100 may include glass, plastic, polypropylene (PP),polyethylene (PE) or polycarbonate (PC). The polycarbonate (PC) has thesuperior light resistance, heat resistance and strength among the abovematerials. The cover 2100 may be transparent so that a user may view thelight source module 2200 from the outside, or may be opaque. The cover2100 may be formed through a blow molding scheme.

The light source module 220 may be disposed at one surface of theradiator 2400. Accordingly, the heat from the light source module 220 istransferred to the radiator 2400. The light source module 2200 mayinclude a light source 2210, a connection plate 2230, and a connector2250.

The member 2300 is disposed on a top surface of the radiator 2400, andincludes guide grooves 2310 into which a plurality of light sources 2210and the connector 2250 are inserted. The guide grooves 2310 correspondto a substrate of the light source 2210 and the connector 2250.

A surface of the member 2300 may be coated with a light reflectivematerial. For example, the surface of the member 2300 may be coated withwhite pigment. The member 2300 reflects again light, which is reflectedby the inner surface of the cover 2100 and is returned to the directionof the light source module 2200, to the direction of the cover 2100.Accordingly, the light efficiency of the lighting apparatus according tothe embodiment may be improved.

For example, the member 2300 may include an insulating material. Theconnection plate 2230 of the light source module 2200 may include anelectrically conductive material. Accordingly, the radiator 2400 may beelectrically connected to the connection plate 2230. The member 2300 maybe formed by an insulating material, thereby preventing the connectionplate 2230 from being electrically shorted with the radiator 2400. Theradiator 2400 receives heat from the light source module 2200 and thepower supply part 2600 and dissipates the heat.

The holder 2500 covers a receiving groove 2719 of an insulating part2710 of an inner case 2700. Accordingly, the power supply part 2600received in the insulating part 2710 of the inner case 2700 is sealed.The holder 2500 includes a guide protrusion 2510. The guide protrusion2510 has a hole and a protrusion of the power supply part 2600 extendsby passing through the hole.

The power supply part 2600 processes or converts an electric signalreceived from the outside and provides the processed or convertedelectric signal to the light source module 2200. The power supply part2600 is received in the receiving groove 2719 of the inner case 2700,and is sealed inside the inner case 2700 by the holder 2500.

The power supply part 2600 may include a protrusion 2610, a guide part2630, a base 2650, and an extension part 2670.

The guide part 2630 has a shape protruding from one side of the base2650 to the outside. The guide part 2630 may be inserted into the holder2500. A plurality of components may be disposed on one surface of thebase 2650. For example, the components may include a DC converter toconvert AC power provided from an external power supply into DC power, adriving chip to control the driving of the light source module 2200, andan electrostatic discharge (ESD) protection device to protect the lightsource module 2200, but the embodiment is not limited thereto.

The extension part 2670 has a shape protruding from an opposite side ofthe base 2650 to the outside. The extension part 2670 is inserted intoan inside of the connection part 2750 of the inner case 2700, andreceives an electric signal from the outside. For example, a width ofthe extension part 2670 may be smaller than or equal to a width of theconnection part 2750 of the inner case 2700. First terminals of a “+electric wire” and a “− electric wire” are electrically connected to theextension part 2670 and second terminals of the “+ electric wire” andthe “− electric wire” may be electrically connected to a socket 2800.

The inner case 2700 may include a molding part therein together with thepower supply part 2600. The molding part is prepared by hardeningmolding liquid, and the power supply part 2600 may be fixed inside theinner case 2700 by the molding part.

FIGS. 14 and 15 are views showing another example of a lightingapparatus according to the embodiment.

FIG. 14 is a perspective view of the lighting apparatus according to theembodiment and FIG. 15 is an exploded perspective view of the lightingapparatus shown in FIG. 14.

Referring to FIGS. 14 and 15, the lighting apparatus according to theembodiment may include a cover 3100, a light source part 3200, aradiator 3300, a circuit part 3400, an inner case 3500, and a socket3600. The light source part 3200 may include the light-emitting deviceor the light-emitting device module according to the embodiment.

The cover 3100 may have a hollow blub shape. The cover 3100 has anopening 3110. The light source part 3200 and a member 3350 may beinserted through the opening 3110.

The cover 3100 may be coupled with the radiator 3300 and may surroundthe light source part 3200 and the member 3350. The light source part3200 and the member 3350 may be blocked from the outside by the couplingbetween the cover 3100 and the radiator 3300. The cover 3100 may becoupled with the radiator 3300 by an adhesive or various schemes such asa rotation coupling scheme and a hook coupling scheme. The rotationcoupling scheme is a scheme where a thread of the cover 3100 is coupledwith a screw groove of the radiator 3300, and the cover 3100 is coupledwith the radiator 3300 by rotation of the cover 3100. The hook couplingscheme is a scheme where a projection of the cover 3100 is inserted intoa groove of the radiator 3300 so that the cover 3100 is coupled with theradiator 3300.

The cover 3100 may be optically coupled with the light source module32200. For example, the cover 3100 may diffuse, scatter, or excite lightprovided from the light-emitting device 3230 of the light source part3200. The cover 3100 may be a type of optical member. The cover 3100 mayhave a phosphor formed on inner/outer surfaces or an inside of the cover3100 to excite the light from the light source part 3200.

The cover 3100 may include an inner surface coated with a milk-whitepaint. The milk-white paint may include a diffusion material to diffuselight. The cover 3100 may have the inner surface of which surfaceroughness is greater than that of the outer surface thereof. The surfaceroughness is provided for the purpose of sufficiently scattering anddiffusing the light from the light source part 3200.

For example, a material of the cover 3100 may include glass, plastic,polypropylene (PP), polyethylene (PE), and polycarbonate (PC). Thepolycarbonate (PC) has the superior light resistance, heat resistanceand strength among the above materials. The cover 3100 may betransparent so that a user may view the light source part 3200 and themember 3500 from the outside, or the cover 3100 may be opaque. The cover3100 may be formed through a blow molding scheme.

The light source part 3200 is disposed at the member 3350 of theradiator 3300, and a plurality of light source parts 3200 may beprovided. In detail, the light source part 3200 may be disposed on atleast one of side surfaces of the member 3350. In addition, the lightsource part 3200 may be disposed at an upper portion of the side surfaceof the member 3350.

Referring to FIG. 15, the light source part 3200 may be disposed atthree of six side surfaces of the member 3350. However, the embodimentis not limited thereto, and the light source part 3200 may be disposedat all side surfaces of the member 3350. The light source part 3200 mayinclude a substrate 3210 and a light-emitting device 3230. Thelight-emitting device 3230 may be disposed on one surface of thesubstrate 3210.

The substrate 3210 has a rectangular plate shape, but the embodiment isnot limited thereto. The substrate 3210 may have various shapes. Forexample, the substrate 3210 may have a circular plate shape or apolygonal plate shape. The substrate 3210 may be provided by printing acircuit pattern on an insulator. For example, the substrate 3210 mayinclude a typical printed circuit board (PCB), a metal core PCB, aflexible PCB, and a ceramic PCB. In addition, the substrate may have aCOB (chips on board) type in which LED chips, which are not packaged,are directly bonded on the PCB. In addition, the substrate 3210 mayinclude a material suitable to reflect light, or the surface of thesubstrate may have a color such as a white color or a silver color toeffectively reflect the light. The substrate 3210 may be electricallyconnected to the circuit part 3400 received in the radiator 3300. Forexample, the substrate 3210 and the circuit part 3400 may be connectedto each other by a wire. The wire may connect the substrate 3210 and thecircuit part 3400 to each other by passing through the radiator 3300.

The light-emitting device 3230 may be a light-emitting diode chip foremitting red, green, blue or UV light. The light-emitting diode chip maybe a lateral type or a vertical type and the light-emitting diode chipmay emit blue, red, yellow or green light.

The light-emitting device 3230 may include a luminescence material. Theluminescence material may include at least one of garnet-based phosphors(YAG, or TAG), silicate-based phosphors, nitride-based phosphors, andoxynitride-based phosphors. The luminescence material may include atleast one of a red luminescence material, a yellow luminescence materialand a green luminescence material.

The radiator 3300 is coupled with the cover 3100, and may radiate heatfrom the light source part 3200. The radiator 330 has a predeterminedvolume, and includes a top surface 3310 and a side surface 3330. Themember 3350 may be disposed on the top surface 3310 of the radiator3310. The top surface 3310 of the radiator 3300 may be coupled with thecover 3100. The top surface 3310 of the radiator 3300 may have a shapecorresponding to an opening 3110 of the cover 3100.

A plurality of heat radiation pins 3370 may be disposed at the sidesurface 3330 of the radiator 3300. The heat radiation pin 3370 mayextend outward from the side surface 3330 of the radiator 3300 or may beconnected to the side surface 3330 of the radiator 3300. The heatradiation pin 3370 may improve heat radiation efficiency by increasing aheat radiation area of the radiator 3300. The side surface 3330 may notinclude the heat radiation pin 3370.

The member 3350 may be disposed on the top surface of the radiator 3300.The member 3350 may be integrated with or coupled to the top surface3310 of the radiator 3300. The member 3350 may have the shape of apolygonal prism. In detail, the member 3350 may have the shape of ahexahedral prism. The member 3350 having the shape of a hexahedral prismincludes a top surface, a bottom surface, and six side surfaces. Themember 3350 may have the shape of a circular prism or the shape of anelliptical prism as well as the shape of a hexahedral prism. When themember 3350 has the shape of a circular prism or the shape of anelliptical prism, the substrate 3210 of the light source part 3200 maybe a flexible substrate.

The light source part 3200 may be disposed at six side surfaces of themember 3350. The light source part 3200 may be disposed at all or someof the six side surfaces of the member 3350. The light source part 3200is disposed at three of the six side surfaces of the member 3350.

The substrate 3210 is disposed at the side surface of the member 3350.The side surface of the member 3350 may be substantially vertical to thetop surface 3310 of the radiator 3300. Accordingly, the substrate 3210and the top surface of the radiator 3300 may be substantially verticalto each other.

The member 3350 may include a material representing thermalconductivity. Thus, heat from the light source part 3200 can be rapidlytransferred to the member 3350. For example, the material for the member3350 may include an alloy of metals such as aluminum (Al), nickel (Ni),copper (Cu), magnesium (Mg), silver (Ag), or tin (Sn). In addition, themember 3350 may include a plastic material having thermal conductivity.The plastic material having thermal conductivity is advantageous in thatit is lighter than the metal and has thermal conductivity in a singledirection.

The circuit part 3400 receives power from the outside, and converts thereceived power suitably for the light source part 3200. The circuit part3400 provides the converted power to the light source part 3200. Thecircuit part 3400 may be disposed at the radiator 3300. In detail, thecircuit part 3400 may be received in the inner case 3500, and may bereceived in the radiator 3300 together with the inner case 3500. Thecircuit part 3400 may include a circuit board 3410 and a plurality ofcomponents mounted on the circuit board 3410.

The circuit board 3410 has a circular shape, but the embodiment is notlimited thereto. That is, the circuit board 3410 may have variousshapes. For example, the circuit board may have an elliptical shape or apolygonal shape. The circuit board 3410 may be provided by printing acircuit pattern on an insulator. The circuit board 3410 is electricallyconnected to the substrate 3210 of the light source part 3200. Forexample, the circuit part 3410 and the substrate 3210 may be connectedto each other by a wire. The wire may be disposed inside the radiator3300 to connect the substrate 3210 to the circuit board 3410. Forexample, a plurality of components 3430 may include a direct currentconverter converting AC power provided from an external power supplyinto DC power, a driving chip controlling driving of the light sourcepart 3200, and an electrostatic discharge (ESD) protective device.

The inner case 3500 receives the circuit part 3400 therein. The innercase 3500 may include a receiving part 3510 to receive the circuit part3400. For example, the receiving part 3510 may have a cylindrical shape.The shape of the receiving part 3510 may be changed according to theshape of the radiator 3300. The inner case 3500 may be received in theradiator 3300. The receiving part 3510 of the inner case 3500 may bereceived in a receiving part which is formed at a bottom surface of theradiator 3300.

The inner case 3500 may be coupled with the socket 3600. The inner case3500 may include a connecting part 3530 coupled with the socket 3600.The connecting part 3530 may have a thread structure corresponding to ascrew groove structure of the socket 3600. The inner case 3500 is aninsulator. Accordingly, the inner case 3500 prevents electric shortbetween the circuit part 3400 and the radiator 3300. For example, theinner case 3500 may include a plastic or resin material.

The socket 3600 may be coupled with the inner case 3500. In detail, thesocket 3600 may be coupled with the connecting part 3530 of the innercase 3500. The socket 3600 may have the structure the same as that of aconventional incandescent light bulb. The socket 3600 is electricallyconnected to the circuit part 3400. For example, the circuit part 3400and the socket 3600 may be connected to each other by a wire. Ifexternal power is applied to the socket 3600, the external power may betransferred to the circuit part 3400. The socket 3600 may have a screwgroove structure corresponding to a thread structure of the connectingpart 3550.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to affect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A light-emitting device comprising: a light-emitting structure comprising a first conductive semiconductor layer, an active layer under the first conductive semiconductor layer, and a second conductive semiconductor layer under the active layer; a reflective electrode under the light-emitting structure; a first metal layer disposed under the reflective electrode and electrically connected to the second conductive semiconductor layer; a second metal layer disposed under the reflective electrode and insulated from the first metal layer; and a contact part electrically connecting the second metal layer to the first conductive semiconductor layer.
 2. The light-emitting device of claim 1, wherein the first metal layer is electrically connected to the reflective layer.
 3. The light-emitting device of claim 1, wherein the first metal layer comprises a first region making contact with a bottom of the second conductive semiconductor layer and a second region extending outward from the first region.
 4. The light-emitting device of claim 1, wherein the second metal layer is disposed under the first metal layer.
 5. The light-emitting device of claim 1, further comprising a first insulating layer between the first metal layer and the second metal layer.
 6. The light-emitting device of claim 5, wherein the contact part is formed through the first insulating layer.
 7. The light-emitting device of claim 5, wherein the first insulating layer is disposed around the first metal layer.
 8. The light-emitting device of claim 1, wherein the first region of the contact part makes contact with a top surface of the first conductive semiconductor layer.
 9. The light-emitting device of claim 1, wherein the second region of the contact part is disposed at lateral sides of the active layer and the second conductive semiconductor layer.
 10. The light-emitting device of claim 9, further comprising a second insulating layer disposed between the second region of the contact part and the active layer and between the second region of the contact part and the second conductive semiconductor layer.
 11. The light-emitting device of claim 1, wherein the contact part is spaced apart from a lateral side of the first metal layer.
 12. The light-emitting device of claim 1, further comprising an ohmic contact layer between the second conductive semiconductor layer and the reflective electrode.
 13. The light-emitting device of claim 1, further comprising an electrode electrically connected to the first metal layer and spaced apart from a lateral side of the light-emitting structure.
 14. The light-emitting device of claim 13, wherein the electrode spaced apart from the lateral side of the light-emitting structure makes contact with a top surface of the first metal layer.
 15. The light-emitting device of claim 1, wherein a plurality of contact parts are provided.
 16. A light-emitting device package comprising: a body; a light-emitting device on the body; and first and second lead electrodes electrically connected to the light-emitting device, wherein the light-emitting device comprises a light-emitting structure comprising a first conductive semiconductor layer, an active layer under the first conductive semiconductor layer, and a second conductive semiconductor layer under the active layer; a reflective electrode under the light-emitting structure; a first metal layer disposed under the reflective electrode and electrically connected to the second conductive semiconductor layer; a second metal layer disposed under the reflective electrode and insulated from the first metal layer; and a contact part electrically connecting the second metal layer to the first conductive semiconductor layer.
 17. The light-emitting device package of claim 16, wherein the second metal layer is disposed under the first metal layer.
 18. The light-emitting device package of claim 16, further comprising a first insulating layer between the first metal layer and the second metal layer, wherein the contact part is formed through the first insulating layer.
 19. The light-emitting device package of claim 16, wherein the contact part comprises a first region making contact with a top surface of the first conductive semiconductor layer and a second region disposed at lateral sides of the active layer and the second conductive semiconductor layer.
 20. A light unit comprising: a substrate; a light-emitting device on the substrate; and an optical member serving as an optical path for light emitted from the light-emitting device, wherein the light-emitting device comprises a light-emitting structure comprising a first conductive semiconductor layer, an active layer under the first conductive semiconductor layer, and a second conductive semiconductor layer under the active layer; a reflective electrode under the light-emitting structure; a first metal layer disposed under the reflective electrode and electrically connected to the second conductive semiconductor layer; a second metal layer disposed under the reflective electrode and insulated from the first metal layer; and a contact part electrically connecting the second metal layer to the first conductive semiconductor layer. 